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Date:   Sun, 18 Aug 2019 10:16:50 +0200 (CEST)
From:   Richard Weinberger <richard@nod.at>
To:     Gao Xiang <hsiangkao@aol.com>
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Al Viro <viro@zeniv.linux.org.uk>,
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        linux-kernel <linux-kernel@vger.kernel.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        Stephen Rothwell <sfr@canb.auug.org.au>, tytso <tytso@mit.edu>,
        Pavel Machek <pavel@denx.de>, David Sterba <dsterba@suse.cz>,
        Amir Goldstein <amir73il@gmail.com>,
        Christoph Hellwig <hch@infradead.org>,
        Darrick <darrick.wong@oracle.com>,
        Dave Chinner <david@fromorbit.com>,
        Jaegeuk Kim <jaegeuk@kernel.org>, Jan Kara <jack@suse.cz>,
        torvalds <torvalds@linux-foundation.org>,
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        Gao Xiang <gaoxiang25@huawei.com>
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Subject: Re: [PATCH] erofs: move erofs out of staging
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----- Ursprüngliche Mail -----
>> While digging a little into the code I noticed that you have very few
>> checks of the on-disk data.
>> For example ->u.i_blkaddr. I gave it a try and created a
>> malformed filesystem where u.i_blkaddr is 0xdeadbeef, it causes the kernel
>> to loop forever around erofs_read_raw_page().
> 
> I don't fuzz all the on-disk fields for EROFS, I will do later..
> You can see many in-kernel filesystems are still hardening the related
> stuff. Anyway, I will dig into this field you mentioned recently, but
> I think it can be fixed easily later.

This is no excuse to redo all these bugs. :-)

I know that many in-kernel filesystems trust the disk ultimately, this is a
problem and huge attack vector.

Thanks,
//richard